Magnetic latching relay



Dec. 3, 1968 R. 1.. MARTIN 3,414,852

MAGNETIC LATCHING RELAY Filed April 27, 1967 2 Sheets-Sheet 1 1205527-1;. MAeT/u INVENTOR.

BY 154211! 0AM Dec. 3, 1968 R. 1.. MARTIN 3,414,852

MAGNETIC LATCHING RELAY Filed April 27, 1967 2 Sheets-Sheet 2,

64 HOSEET 1,. MfiQT/N F INVENTOR.

38 63 BY 4o 42 I 5 M a/WV United States Patent 3,414,852 MAGNETICLATCHING RELAY Robert L. Martin, La Canada, Calif., assignor toConsolidated Electronics Industries Corp., New York, N.Y., a corporationof Delaware Continuation-impart of application Ser. No. 513,908, Dec.13, 1965. This application Apr. 27, 1967, Ser. No. 634,144

7 Claims. (Cl. 335-170) ABSTRACT OF THE DISCLOSURE A bi-stable,switching device that is capable of alternate'ly positioning a movablecontact against one or another of two fixed contacts. Motion of themovable contact is controlled by energizing one or another of two coilswith direct current to position the movable contact against the fixedcontact which cooperates with the energized coil, while the other coilremains deenergized. When the movable contact has completed its movementto the fixed contact the coil is de-energized and the movable contactwill remain held or latched in the position referred to by the magneticfield induced by the permanent magnet elements where the air gap betweenthe magnet and the movable contact is the smaller. When the latching isto be released, the other coil is energized. This will create a magneticfield stronger than the field created by the permanent magnet and themovable contact will shift to the opposite fixed contact.

The design of micro-miniature equipment has advanced very remarkably inrecent years with the calls upon it placed by missile and space vehicledemands. Although technology has evolved many successful micro-miniaturerelays and switches with acceptable performance characteristics therecontinue to be other problems to be overcome. One of these is complexityof assemblies which increases the prospect of devices getting out oforder. Another is high cost of devices which, especially when somewhatcomplex, require a considerable amount of careful assembly andadjustment to operate dependably. Other shortcomings include a lack ofdesirable life span and insuflicient degree of precision especially whenworking with tolerances which need to be measured in a few thousandthsof an inch, and frequently less.

Applicants copending application Ser. No. 513,908, filed Dec. 13, 1965,now Patent No. 3,335,376, of which this is a continuation-in-part,discloses a satisfactory structure suitable for micro-miniature usewherein a dependable procedure is revealed making it possible toconstruct a switching arrangement with stationary or fixed contactsanchored in position by the initial tooling operation and which makesuse of an axially located tiltably mounted armature positivelyconstructed to extremely low tolerances and adapted to operate betweenthe two fixed contacts.

Another of applicants copending applications Ser. No. 633,289 filed Apr.24, 1967, discloses a very acceptable method for assembling devices ofthe character disclosed by appropriate tooling so that no subsequentadjustment is either necessary or possible.

It is among the objects of the invention herein disclosed to provide anew and improved magnetic latching relay of comparable constructionreadily adapted to subminiature proportions and wherein a movablearmature is independent of spring action for its operation.

Another object of the invention is to provide a new and improvedmagnetic latching relay which makes use of magnetic fields set up bypermanent magnets as a latching medium for holding a movable armature inone position or another.

Still another object of the invention is to provide a new and improvedmagnetic latching relay making use of permanent magnets for the latchingoperation which employs a relative minimum number of moving parts, whichis simple in construction thereby lending itself to a very simpleassembly procedure made possible by simple and inexpensive tooling,which is easily varied in size and proportion to meet different demands,capabilities, current load, etc., which is of inexpensive constructionand which can be produced from relatively inexpensive materials.

With these and other objects in view, the invention consists of theconstruction, arrangement, and combination of the various parts of thedevice, whereby the objects contemplated are attained, as hereinafterset forth, pointed out in the appended claims and illustrated in theaccompanying drawings.

In these drawings:

FIGURE 1 is a side perspective view of the device abundantly broken awayto show the relationship of the various parts;

FIGURE 2 is an exploded perspective view to better reveal the form, sizeand relationship of parts;

FIGURE 3 is a longitudinal sectional view through the device showing thearmature in a position such that the movable contact is in engagementwith one of the fixed contacts;

FIGURE 4 is a longitudinal sectional view on the line 44 of FIGURE 3;

FIGURE 5 is a cross-sectional view on the line 5-5 of FIGURE 3;

FIGURE 6 is a cross-sectional view on the line 66 .of FIGURE 3;

FIGURE 7 is a fragmentary cross-sectional view on the line 7-7 of FIGURE3; and

FIGURE 8 is a fragmentary longitudinal sectional view on the line 88 ofFIGURE 3.

In an embodiment of the invention which has been chosen primarily forthe purpose of illustrating the principle involved herein there is showna magnetic (latching relay consisting in the main of an operatingassembly indicated generally by the reference character 10 lodged withina substantially cylindrical housing 11 having one closed end 12 andhaving at the opposite end a header 13. The header serves as a supportfor a series of pins or soldering posts some of which are shown inFIGURES 1, 2, 3 and 4 identified by the reference characters 14, 15, 16,and 17. In the device here under consideration two separate coil membersand 21 are disclosed each constructed in substantially the same fashion.The coil member 20 consists of opposite annular discs 22 and 23interconnected by a sleeve 24, and within which is wound a substantiallyconventional coil 25. The coil member 21 is similarly constructed ofspaced annular discs 26 and 27 interconnected by means of a sleeve 28and housing a coil 29. Appropriate wrappings 30 and 31 surround thecoils.

At the inner end of the housing 11 the sleeve 24 projects slightly toform opposite spaced arcuate segments 32 and 33 which serve to positiona somewhat arcuate semicircular magnetic plate 34. There are recesses 35and 36 which receive respectively the segments 32 and 33 andintermediate the recesses is a pole face 37.

At the opposite or outer end of the housing 11 is a similarsubstantially arcuate semicircular magnetic plate 38 comprehendingrecesses 39 and 40 which receive respective segments 41 and 42 which areextensions of the sleeve 28. Here also there is a pole face 43 spanningthe distance between the two recesses 39 and 40.

Intermediate the coil members 20 and 21 is a pair of magnetic sectors 44and 45 which comprise a permanent magnet member. The magnetic plates 34and 38 are soft iron magnetic material.

Within the sleeve 24 is a passage 46 which is in axial alignment with asimilar passage 47 through the sleeve 28. For mounting an armature 50 inthe combined passages 46, 47, there is provided a bushing 51 in whichlateral openings 52 and 53, which admit inner ends of the respectivemagnetic sectors 44 and 45, are clearly shown in FIGURES 1, 2, 3 and 6.The armature 50 is pivotedly mounted upon the bushing 51 by means of apivot pin 54 which rotates in holes 56 and 57. A positioning strap 58fastened to the bushing 51 has an end 59 which overlies the disc 22 atthe inner end of the housing thereby to hold the bushing in properposition, and accordingly properly position and mount the armature 50,so that it can reciprocate laterally within the passages 46 and 47.

A stationary support indicated generally by the reference character 60,of appropriate dielectric material, is secured in a position adjacentthe header 13 by mounting it as shown on the outside face of themagnetic plate 38. The stationary support 60 is annular in shape asreadily appears in FIGURE 2 and is provided with a central opening 61 ofample diameter. Fixed contacts 62 and 63 are anchored in the stationarysupport 60 in positions extending into the central opening 61. In theembodiment shown the fixed contacts are substantially cylindrical rodswhich are embedded initially in position by use of an appropriatefixture which provides a precise spacing between adjacent edges of thecontacts. A movable contact 64 is provided on the outer end of thearmature 50, preferably coined to give it a precise dimension and moreparticularly a precise transverse size measured in the direction betweenthe fixed contacts 62 and 63, as best seen in FIGURE 3. A flexiblepigtail 65 connects the movable contact 64 with one of the pins 16.Similar pigtails 66 and 67, suggested schematically in FIGURE 3, connectthe movable contacts 62 and 63 with respective pins 15 and 17. Otherpins are provided for attachment of opposite ends of wires from thecoils 20 and 21, not shown in the interest of clarity.

To complete the structure of the operating assembly 10, there isprovided a magnetic sleeve 70 which surrounds the exterior of both ofthe coil members 20 and 21 and which also overlies outside edges of themagnetic plates 34 and 38 and also the outside edges of the magneticsectors 44 and 45. The magnetic sleeve accordingly completes themagnetic paths for the permanent magnet elements and also assists inholding the coil members and related parts in a compact unitaryoperating assembly. An insulating jacket 71 extends over the entireexterior of the magnetic sleeve.

In operation the permanent magnet elements serve to induce continuousmagnetic fields through two closed loop magnetic paths. One pathconsists of the inner magnetic plate 34, the adjacent portion of themagnetic sleeve 70, the magnetic sectors 44 and 45 and the adjacentportion of the armature 50. The other magnetic path is formed by theouter magnetic plate 38, the adjacent portion of the magnetic sleeve 70,the magnetic sectors 44 and 45 and the adjacent portion of the armature50. The armature 50 is thus simultaneously attracted to both magneticplates by magnetic forces of intensities inversely proportioned to airgap distances of respective air gaps 72 and 73. In the position ofadjustment of FIGURE 3 it will be noted that the air gap 72 is largerthan the air gap 73. When the armature 50 has been actuated byenergizing the coil 29 the movable contact 64 will be pivoted or swungto a position of engagement with the fixed contact 62 as shown inFIGURES 3 and 7, because the intensity of the magnetic field created byexcitation of the coil 29 is substantially greater than any magneticfield generated by the permanent magnetic loops. In this position,however, the attraction of the magnetic plate 38 will be greater thanthe attraction of the magnetic plate 34 so that when 4 the coil 29 isde-energized the armature 50 will be held or latched in position againstthe fixed contact 62.

After the armature has been latched as just described should the coil 25be energized, the magnetic field thus created will be sufiiciently greatto overcome the magnetic attraction of the permanent magnetic loops andwill cause the armature 50 to pivot counterclockwise in an oppositedirection until the movable contact 64 is pulled into engagement withthe fixed contact 63. When this happens the size of the air gaps 72 and73 will be reversed, the air gap 72 becoming smaller and the air gap 73becoming larger. Consequently when the coil 25 is de-energized themovable contact 64 will be held or latched in a position of engagementwith the fixed contact 63 by reason of the greater attraction of themagnetic loop formed by the magnetic plate 34 in contrast with theweaker magnetic loop of the magnetic plate 38. This position of coursecan be immediately changed by re-energizing the coil 29 which willreciprocate motion of the armature 50 and again draw the movable contact64 into engagement with the fixed contact 62. The relay may berepeatedly cycled in the manner described by alternately andindividually energizing and de-energizing the coils 25 and 29 withdirect current.

While the invention has herein been shown and described in what isconceived to be the most practical and preferred embodiment, it isrecognized that departures may be made therefrom within the scope of theinvention, which is to be accorded the full scope of the claims so as toembrace any and all equivalent devices.

Having described the invention, what is claimed as new in support ofLetters Patent is:

1. A magnetic latching relay for an electric circuit comprising anoperating assembly having opposite ends, a coil form including aplurality of longitudinally spaced coils located between opposite ends,a permanent magnet member located between said coils, and a magneticplate on the outer side of each coil, a stationary support in saidassembly adjacent one end and a pair of transversely spaced fixedcontacts mounted on said support, said coil form having an open axialpassage therethrough, an armature in said passage mounted forreciprocating movement in said assembly, whereby opposite ends of saidarmature are adapted to change their respective positions, one end ofsaid armature having a movable contact located intermediate said fixedcontacts, said movable contact when in engagement with one of said fixedcontacts upon energization of one of said coils forming air gaps ofdifferent distances between opposite ends of said armature and therespective magnetic plates, said different distances being reversed inrelative magnitude when the movable contact is in engagement with theother fixed contact upon de-energization of said one coil andenergization of the other coil, whereby when one of the coils has beenenergized the armature is shifted to a corresponding position andlatched temporarily by permanent magnetic attraction in said lastposition after the coil is de-energized.

2. A magnetic latching relay as in claim 1 wherein there is a magneticsleeve surrounding said coils, said magnetic plate and said permanentmagnetic member which completes the magnetic path.

3. A magnetic latching relay as in claim 1 wherein the fixed contactsare anchored in non-adjustable position in said support and the armatureis free of engagement with the magnetic plate in all positions of thearmature.

4. A magnetic latching relay as in claim 1 wherein the magnetic platesare substantially arcuate in form and have each a central open areasurrounding the respective end of the armature. I

5. A magnetic latching relay as in claim 1 wherein the permanent magnetmember comprises a pair of substantially sector shaped relatively fiatelements spaced opposite each other on respectively opposite sides ofsaid passage.

6. A magnetic latching relay as in claim 1 wherein a bushing provides acarrier for said pivotal mounting of the armature, said bus-hing beingshorter than said passage and having portions on opposite sides of saidpermanent magnet member engaging said coil form within said passage.

7. A magnetic latching relay as in claim 1 wherein there is a housingsurrounding said assembly and a header at one end of the assembly havingelectric contact posts thereon connected to said respective movable andfixed contacts.

6 References Cited UNITED STATES PATENTS 9/1961 Didier 335-470 8/1965Kramer 335-254 BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner.

